The number guess game in Common Lisp (from Land of Lisp), to compare to the Ruby implementation

number-guess.cl

(defparameter *small* 1)
(defparameter *big* 100)

(defun guess-my-number ()
  (ash (+ *small* *big*) -1))

(defun smaller ()
  (setf *big* (1- (guess-my-number)))
  (guess-my-number))

(defun bigger ()
  (setf *small* (1+ (guess-my-number)))
  (guess-my-number))

(defun start-over ()
  (setf *small* 1)
  (setf *big* 100)
  (guess-my-number))

number_guess.rb

def start_over
  @small, @big = 1, 100
  guess
end

def guess
  (@small + @big) >> 1
end

def smaller
  @big = guess + 1
  guess
end

def bigger
  @small = guess - 1
  guess
end

start_over

NumberGuess.java

import java.io.Console;

public class NumberGuess {
  private int small;
  private int big;
  private int guess;

  private void guess(){
    this.guess = nextGuess();
    String verdict = System.console().readLine(guess + ": smaller/bigger/start-over? ");
    if ( "smaller".equals(verdict) ) {
      smaller();
    } else if ( "bigger".equals(verdict) ) {
      bigger();
    } else if ( "start-over".equals(verdict) ) {
      startOver();
    } else {
      throw new IllegalArgumentException("Don't know " + verdict);
    }
  }

  private void startOver(){
    this.small = 1;
    this.big = 100;
    guess();
  }

  private void smaller(){
    this.big = nextGuess() - 1;
    guess();
  }

  private void bigger(){
    this.small = nextGuess() + 1;
    guess();
  }

  private int nextGuess(){
    return ( this.small + this.big ) >> 1;
  }

  public static void main(String[] args){
    (new NumberGuess()).startOver();
  }
}